Fix before first heading check

* lisp/org.el (org-before-first-heading-p): If point is on an org-mode heading line then we are not before the first heading

If point is anywhere on the first line of the first heading then we
are not before the first heading.  This makes
org-before-first-heading-p returns t instead of nil when on the '*' or
blank of the first level 1 heading in an org file.

This was noticed when the first heading has an encryption
tag :crypt:. C-c C-r would not decrypt this entry if point is at the
beginning of the line since it was considered before the first
heading.

lisp/org.el

@@ -19195,6 +19195,7 @@ This version does not only check the character property, but also
 (defun org-before-first-heading-p ()
   "Before first heading?"
   (save-excursion
+    (end-of-line)
     (null (re-search-backward "^\\*+ " nil t))))
 
 (defun org-on-heading-p (&optional ignored)